User Manual

Rockwell Automation Publication 1752-UM001E-EN-P - June 2014 69
Configure Local I/O Chapter 6
6. Set the Channel Mode for the safety input.
7. If you set the Channel Mode to Test pulse from test output, choose the test
output to use in combination with the safety input by selecting it from the
Te s t S o u r c e p u l l - d o w n l i st .
8. Set the Dual Channel mode and Discrepancy Time.
Setting Dual Channel mode enables the status of two inputs to be
evaluated and reflected in I/O tags. The discrepancy time between
changes in the status of two inputs can also be evaluated. The
combinations that can be set are pre-defined. The Discrepancy Time can
be set between 0…65530 ms in 10 ms increments. Both inputs must
change state within the discrepancy time or an error occurs.
Channel Mode Description
Not used The input channel is not connected to an external device. This is the default.
Test pulse from test
output
Use this mode when you are achieving a Category 4 input circuit. This mode assumes
that you have connected your input device to a Pulse Test Source, and then wired to
this input terminal. This enables detection of short circuits with the power supply
line (positive side), earth faults, and short circuits with other input signal lines
(channel-to-channel shorts). The controller must know that the input signal is being
pulse-tested, or nuisance trips may occur.
See the Example: Input Channel as Test Pulse from Test Output on page 70.
Used as a safety input Use this mode to connect to a safety device with a semiconductor output, such as a
light curtain.
Used as a standard
input
Use this mode to connect to a standard (non-safety) device.
TIP
The Channel mode of the test output selected is automatically set to
Pulse Test Output.
Channel Mode Description
Single Channel The safety input terminal is used independently.
Dual Channel Equivalent The safety input terminal is used as a Dual Channel Equivalent with a
pair safety input terminal.
Dual Channel Complementary The safety input terminal is used as a Dual Channel Complement with
a paired safety input terminal.
TIP
The controller supports function blocks with functionality
equivalent to Dual Channel mode. In many case,
annunciation and troubleshooting of system faults is easier
when the function blocks are used to detect faults rather
than the SmartGuard hardware. If you wish to use the
function blocks to detect system faults, the safety inputs
must be configured for single channel.